More than a dozen schools remained closed in the western German city of Duisburg on Monday after receiving far-right threats.

Fifteen secondary schools were shut, with some 17,980 pupils affected, a spokeswoman for the district administration told dpa.

Signs saying “school closed’’ were put up at several of the affected institutions on Monday morning, according to a dpa reporter at the scene.

It came after the school administration of the Gesamtschule Duisburg-Mitte school received a note on Friday containing threats and right-wing extremist statements, according to the police.

The sender, whose identity remained unknown, had threatened to commit criminal acts at the school on Monday, it said.

The school then received another note on Sunday, again containing threats – this time against other schools in the area as well, police said.

However, police said Duisburg’s state security service assumed the threats to be a hoax.

Regardless, affected schools switched to distance learning on Monday as a precautionary measure.

(dpa/NAN)